1. Field of the invention
The present invention relates to novel synergistic detergent and disinfectant combinations and to an improved method for effectively decontaminating biofilm-coated surfaces. Types of surfaces comprise: the inner surface of aqueous liquid-supplying lines, particularly fresh water lines such as those supplying water to dental instruments regularly used by dentists, dental surgeons or dental hygienists, the inner surface of lines of larger diameters and the inner surface of containers having received aqueous liquids for a sufficient length of time to have allowed growth of microorganisms, their deposition and their organization as a biofilm to adhere to the walls of the containers. More particularly, the present invention relates to detergent-disinfectant combinations for dislodging biofilm formed or accumulated on contaminated surfaces for destroying the microorganisms contained therein. The preferred compositions are particularly suitable for water pipes of dental instruments which are of a small diameter, because no scrubbing is needed for maximal efficiency in a convenient time of decontamination.
2. Brief description of the prior art
Dentists, dental surgeons and dental hygienists and their patients are well aware of the importance of meticulously sterilizing and disinfecting dental instruments. Indeed, since dental instruments are used directly in a patient's mouth, when bleeding may sometimes occur as a result of a dental procedure, it is of paramount importance to minimize the presence of microorganisms carried by dental instruments. The microorganisms can of course range from relatively harmless bacteria to dangerous pathogens. Consequently, efforts are deployed to remove microorganisms from dental instruments and from the fresh water lines feeding dental instruments such as air/water guns, high speed water turbines or ultrasonic tartar removers. For most hand held dental instruments, thermal sterilization remains one of the best methods for eradicating the presence of microorganisms. However, thermal sterilization is obviously not practical for the decontaminating of fresh water lines which remain to this date difficult to rid of microorganisms.
It is well known in the dental profession that small diameter pipes carrying fresh water are contaminated by bacteria and other microorganisms contained in the water flowing through them. Some of the microorganisms inevitably adhere to the inner walls of the pipes and accumulate together with microscopic sediments or other substances into what is commonly known as a biofilm. The biofilm quickly and tenaciously coats the inner walls of the pipes. The biofilm becomes a culture medium for more microorganisms. For example bacteria population will rapidly reach alarming levels which will also be found in the water discharge from the dental instruments connected to the fresh water line. For example, the average bacteria count in the water discharge of dental instruments is known to be of approximately 200,000 colony forming units per milliliter (cfu/ml) and in some extreme cases can reach 10,000,000 cfu/ml.
It has been suggested to use sterile water, to drain the fresh water lines during periods of non-use or to use filters to catch the microorganisms. However, none of those methods have been shown to effectively remedy the microorganism proliferation for any length of time.
It is also known in the art to use disinfectants such as povidone-iodine at a concentration of approximately 10% to reduce the number of microorganisms in small diameter water lines. It is further also known that a mixture of mandelic and lactic acids reduce the number of sensitive microorganisms in contaminated catheters. However, such disinfection is somewhat superficial since it fails to effectively attack and destroy the microorganisms found in the biofilm. Consequently, the disinfection effect is short-lived. After 24 hours of treatment with povidone-iodine, the number of bacteria is greatly reduced but quickly begin to rise after eight days.
It is also known to use a detergent such as polyoxyethylene sorbitan monooleate (Tween 80.TM.) at approximately 4% concentration to dislodge biofilm from small diameter water lines used in dental equipment. However, the use of detergent alone does not effectively destroy the microorganism population.
Accordingly there remains a need for a composition for decontaminating small diameter water lines for dental equipment which will effectively dislodge and eliminate a biofilm and at the same time destroy the microorganism flora in the fresh water and in the dislodged biofilm.